Self-locking coupling nut for electrical connectors

ABSTRACT

An electrical connector adapted to be secured to a mating electrical connector. A first member extends outwardly from the connector shell with indentations formed on a radially extending surface of the first member. A coupling nut is axially aligned with the connector and surrounds a portion of the connector outer shell. A pair of longitudinally extending slots are formed on the outer surface of the coupling nut. A second member is longitudinally movable in the slot and rotatable with the coupling nut. Protrusions on the second member surface interact with the first member indentations for varying the tightness between the electrical connector and the mating electrical connector. A spring member is positioned adjacent the second member for urging the second member protrusions to interact with the first member indentations. Indicator means are provided on the outer surface of the coupling nut. The second member extends to the outer surface of the coupling nut, and alignment of the second member with the indicator means provides a visual and tactile indication of the desired degree of tightness between the mated connectors.

United States Patent [1'91 Johnson 1451 Apr. 30, 1974 SELF-LOCKING COUPLING NUT FOR ELECTRICAL CONNECTORS [75] Inventor: Lyle F. Johnson, Manhattan Beach,

Calif.

[73] Assigneez Matrix Science Corporation,

- Torrance, Calif.

22 Filed: Dec. 18, 1972 21 Appl. No.: 315,948

[52] US. Cl. 339/89 R, 339/91 R [51] Int. Cl I-I0lr 13/54 [58] Field of Search 339/89-91 [56] References Cited UNITED STATES PATENTS 3,462,727 8/1969 Blight et al 339/89 M 3,601,764 8/1971 Cameron 339/89 M 3,393,927 7/1968 Kelly et al 339/90 R 3,552,777 1/1971 Heinrich et a]. 339/89 R 3,594,700 7/1971 Nava et al 339/89 R 3,669,472 6/1972 Nodsady 339/89 R FOREIGN PATENTS OR APPLICATIONS 2,002,273 2/l969 France; 339/90 R Primary Examiner-Joseph H. McGlynn Attorney, Agent, or Firm-Nilsson, Robbins & Berliner [57] ABSTRACT An electrical connector adapted to be secured to a mating electrical connector. A first member extends outwardly from the connector shell with indentations formed on a radially extending surface of the first member, A coupling nut is axially aligned with the connector and surrounds a portion of the connector outer shell. A pair of longitudinally extending slots are formed on the outer surface of the coupling nut. A second member is longitudinally movable in the slot and rotatable with the coupling nut. Protrusions on the second member surface interact with the first member indentations for varying the tightness between the electrical connector and the mating electrical connector. A spring member is positioned adjacent the second member for urging the second member protrusions to interact with the first member indentations. Indicator means are provided on the outer surface of the coupling nut. The second member extends to the outer surface of the coupling nut, and alignment of the second member with the indicator means provides a visual and tactile indication of the desired degree of tightness between the mated connectors.

4 Claims, 6 Drawing Figures PATENTEDAPR 30 m4 SHEET 1 OF 2 I PATENTEWRMM 8808.580 SHEET 2 UF 2 SELF-LOCKING COUPLING NUT FOR ELECTRICAL CONNECTORS BACKGROUND or THE INVENTION 1. Field of the invention The field of art to which the invention pertains includes the field of electrical connectors, particularly with respect to a self-locking coupling nut for use with an electrical connector which provides a visual and tac- I connectors, one of which contains the self-locking coutile indication when a desired degree of tightness has been attained between mating electrical connectors.

2. Description of the prior art The best known prior art is found in US. Pat. No.

Self-locking electrical connectors have been utilized in the aircraft industry to replace the practice of locking threaded electrical connectors with safety wire. In one form of a self-locking electricalconnector, a plurality of balls are mounted in the flange of a connector shell. A sleeve is positioned around the connector shell and rotation of the sleeve urges the balls toward a flange having a plurality of ball receiving indentations. As the sleeve is rotated .to tighten the connection, the indentations engage and disengage the balls which move axially under the influence of a spring. As the threaded connection becomes tighter, it becomes more difficult to move the indentations past the balls. A visual indication 'of the properly mated condition is provided through an opening in the sleeve wherein a plate member may be viewed in the correct position when the locked condition of the connectors has occurred.

The above-mentioned structure is relatively complex to assemble in view of the use of the balls in the sleeve. In addition, such a structure is relatively expensive since the parts must be accurately machined for use with the balls. Moreover, where the electrical connector is to be secured to a mated electrical connector in an inaccessible position, it has been found that the visual indication of the locked condition cannot be determined by the operator.

SUMMARY OF THE INVENTION An electrical connector adapted to be secured to be a mating electrical connector. A first member extends outwardly from the electrical connector shell and has discontinuities formed on a radially extending surface of the first member. A coupling nut is axially aligned with the connector member and surrounds a portion of the connector outer shell. A longitudinally extending slot is formed on the outer surface of the coupling nut. A second member is movable in the slot and has discontinuities on the surface thereof which interact with the first member discontinuities for the varying degree of tightness between the electrical connector and a mating electrical connector when the connectors are secured together.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of an electrical connector shell and a self-locking coupling nut made in accordance with the invention;

FIG. 2 is a side view, in section, of a pair of mating electrical connectors, one of which contains the selflocking nut of FIG. 1;

FIG. 3 is a side view, in section, of the electrical connectors of FIG. 2 in a fully mated condition;

pling nut of FIG. 4; and

FIG. 6 is a side view, in section, of the electrical connectors of FIG. in a fully mated condition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, there is shown in FIG. 1, an exploded perspective view of a connector shell and a self-locking coupling nut made in accordance with principles of the invention. The connector shell 12 comprises a rear cylindrical portion 14 which typically may be threaded on a portion of its outer surface 16 so as to mount the shell on a bulkhead or other terminal structure. The connector shell further comprises a front cylindrical portion 18. A radially extending flange 22 is formed integral with the cylindrical shell at the junction of the front cylindrical portion 18 and the rear cylindrical portion 14. The flange contains a front surface 23 and a rear surface 24. A plurality of radially formed indentations 26 extend inwardly from the rear surface 24 and radially to the flange outer surface 28.

A coupling nut 32 is adapted to be positioned over the connector shell 12 from the front end thereof and comprises a reduced diameter front bore portion 34 and an enlarged diameter rear bore portion 36. The junction of the front bore portion 34 and the rear bore portion 36 defines a rearwardly facing shoulder 38. An annular groove 42 is formed at the rear end of the rear bore portion 36. A pair of notches 44 are formed in the rear bore portion 36 of the coupling nut and extend from the rear surface 46 of the coupling nut to a rearwardly facing shoulder 48. The notches 44 are normally formed apart on the connector shell. The outer surface 52 of the rear bore portion is knurled to facilitate rotation of the coupling nut 32. In addition, circumferentially extending raised indicator members 54 are positioned on the outer surface 52 and extend on either side of the notches 44. The front bore portion 34 of the coupling nut 32 contains threads 56.

A clutch plate 62 is formed of a cylindrical disc whose front surface 63 contains a plurality of protrusions 64 which extend in a forward direction. As shown in FIG. 2, the disc is mounted on the outer surface of the rear cylindrical portion 14 'of the shell with the front surface 63 abutting the surface 24. The clutch plate also contains a pair of outwardly extending flanges 66 which are positioned in the notches 44 and abut the shoulder 48. The outer surface 67 of the flanges is flush with the knurled outer surface 52. A wave spring 68, having a disc shape, is positioned behind the clutch plate 62. Positioned behind the wave spring 68 is a washer 72. The washer 72 is secured in the rear bore portion 36 by means of a retaining ring 74 which is positioned in the annular groove 42.

Referring again to FIG. 2, the connector shell 12 is shown assembled with the coupling nut 32, the clutch plate 62, the wave spring 68, the washer 72 and the retaining ring 74 positioned thereon. Mounted within the interior of the connector shell 12 is an insulator 82 having a socket contact 84 positioned in the front end thereof. The front end of the socket contact extends forward from the front surface of the insulator 82. A conductor 86, which normally is soldered or crimped to the socket 84, extends rearwardly in the insulator 82. While only one socket contact 84 and one conductor 86 are shown, it should be understood of course, that a plurality of sockets and associated conductors are normally mounted in the insulator 82.

A receptacle shell 92 is adapted to be mated with the shell 12 and contains an insulator 94 therein. The insulator 94 contains a pin contact 96 at the front end with a forwardly extending portion adapted to be mated with the socket contact 84. A conductor 98, which may be soldered or crimped to the pin contact 96, is positioned in the rear of the insulator 94. The front outer surface of the receptacle shell 92 contains threads 102 which are adapted to be mated with the threads 56 formed in the front bore portion 34 of the coupling nut 32.

When the connectors of FIG. 2 are mated, the pin contact 96 is inserted in the socket contact 84. In addition, the receptacle shell 92 is positioned between the outer surface of the connector portion 18 and the threaded bore portion 34. The coupling nut 32 is rotated so that the threads 56 engage the threads 102 on the outer surface of the receptacle shell 92. When the front end 104 of the shell 92 abuts the front surface 23 of the flange 22, the connector members are in an initial mated condition. Then the coupling nut 32 moves forward with respect to the shell 12 upon further rotation thereof. As can be seen in FIG. 3, while the coupling nut 32 moves forward, the rear surface 24 of the flange 22 abuts the front surface 63 of the clutch plate 62 preventing the clutch plate 62 from moving forward. Simultaneously, the clutch plate 62 rides rearwardly along the longitudinal axis of the notch 44. Since the clutch plate 62 has its flanges 66 positioned in the notches 44, the rotation of the coupling nut with respect to the connector shell causes the protrusions 64 in the clutch plate to ride in and out of the indentations 26 formed in the flange 22.

As the coupling nut 32 rotates, the spring 68 is compressed so that as the washer 72 and the retaining ring 74 move closer toward the clutch plate 62. Thus, the protrusions 64 have greater difficulty moving in and out of the indentations 26 in the flange 22 with further rotation of the coupling nut 32. When the flanges 66 are aligned with the ridges 54 on the outer surface of the coupling nut, the electrical connectors are in a locked condition. In addition, it should be noted that should visual alignment of the ridges 54 with the flanges 66 be'not possible, the operator can feel the ridges and the flange and determine that the connectors are in the locked condition.

The clutch plate 62 has been illustrated with protrusions 64 which move in and out of indentations 26 formed on the flange 22. It should be understood, of course, that the rear surface of the flange 24 could contain protrusions which would interact with indentations formed on the clutch plate 62.

Referring now to FIG. 4, there is shown an alternative arrangement for the self-locking coupling nut made in accordance with the invention. In FIG. 4, the coupling nut 32 is similar to that used in the embodiment of FIG. 1. The connector shell 212 comprises a rear cylindrical portion 214 which is threaded on its outer surface 216 in a similar manner as the connector shell of FIG. 1. However, the radially extending flange 222 does not contain indentations. Instead, the radially extending flange 218 contains a pair of slots 222 on opposite sides of the shell. A clutch plate 224 is formed of a cylindrical disc 226 having a plurality of indentations 228 formed on its rear surface. In addition, the clutch plate contains a pair of outwardly extending flanges 232. A pair of tabs 234 extends forwardly from the outer end of each of the flanges 232 in a direction parallel to the longitudinal axis of the connectors and forms an extension of the flanges. When the clutch plate is positioned on the connector shell, the tabs 234 fit into the slots 222 formed on the flange 218.

Positioned adjacent and directly behind the clutch plate 224 is a lock ring 242 formed of a cylindrical disc. Formed on the front surface of the lock ring are a plurality of protrusions 244. In addition, a pair of opposed outwardly extending flanges 246 extends from the outer surface of the lock ring. The flanges 246 are inserted in the notches 44 of the coupling nut 32. Positioned behind the lock ring is the wave spring 68, a washer 72, as well as a retaining ring similar to that utilized in the arrangement of FIG. 1.

It should be noted that the operation of the device of FIGS. 4-6 is similar to that of FIGS. 1-3. However, the lock ring 242 of FIGS. 4-6 is fixably rotated with the coupling nut 32 rather than the clutch plate as in the arrangement of FIGS. l-3. It should be noted that the arrangement of FIGS. 4-6 enables the clutch plate and lock ring to be readily replaced should wear occur between the indentations and protrusions formed on the clutch plate and lock ring, respectively. In the embodiment of FIG. 1, since the indentations are formed on a flange fixed directly to the connector shell, it has been found necessary to manufacture a special connector shell therefor. In the embodiments of FIGS. 4-6, the conventional connector shell can be easily modified so that the slots 222 are formed therein for insertion of the tabs 234 formed on the clutch plate. Additionally, it should be noted that the position of the indentations and protrusions illustrated in the clutch plate and lock ring, respectively, could also be reversed.

I claim:

1. An electrical connector having an outer shell and adapted to be secured to a mating electrical connector comprising:

a first means extending outwardly from said shell and having spherical discontinuities unitarily formed on a radially extending surface;

a coupling nut axially aligned with said connector member and surrounding a portion of said connector outer shell;

a longitudinally extending slot formed on the outer surface of said coupling nut; and

a second means longitudinally movable in said slot and having discontinuities unitarily formed on the surface thereof and interacting with said first means discontinuities to vary the degree of tightness between said connector member and a mating connector member when said connector members are secured together; and

said discontinuities on one of said means extending along the axis of said connector shell to form depressions on a relatively smooth surface formed in a plane perpendicular to said connector shell axis, and said discontinuities on said other of said means extending along said axis of said connector shell to urging said clutch plate discontinuities to interact with said flange discontinuities.

4. An electrical connector in accordance with claim 3 wherein said flange discontinuities are formed of indentations formed on said flange surface and said clutch discontinuities are formed of protrusions formed on a surface of said clutch plate which is in a plane parallel to the flange surface. 

1. An electrical connector having an outer shell and adapted to be secured to a mating electrical connector comprising: a first means extending outwardly from said shell and having spherical discontinuities unitarily formed on a radially extending surface; a coupling nut axially aligned with said connector member and surrounding a portion of said connector outer shell; a longitudinally extending slot formed on the outer surface of said coupling nut; and a second means longitudinally movable in said slot and having discontinuities unitarily formed on the surface thereof and interacting with said first means discontinuities to vary the degree of tightness between said connector member and a mating connector member when said connector members are secured together; and said discontinuities on one of said means extending along the axis of said connector shell to form depressions on a relatively smooth surface formed in a plane perpendicular to said connector shell axis, and said discontinuities on said other of said means extending along said axis of said connector shell to form a plurality of protrusions extending from a relatively smooth surface formed in a plane perpendicular to said connector shell axis.
 2. An electrical connector in accordance with claim 1 wherein said second means comprises a clutch plate which is rotatable with said coupling nut.
 3. An electrical connector in accordance with claim 2 wherein said first means comprises a flange integrally formed with said connector shell and wherein a spring member is positioned adjacent said clutch plate for urging said clutch plate discontinuities to interact with said flange discontinuities.
 4. An electrical connector in accordance with claim 3 wherein said flange discontinuities are formed of indentations formed on said flange surface and said clutch discontinuities are formed of protRusions formed on a surface of said clutch plate which is in a plane parallel to the flange surface. 